JPH0284932A - Apparatus for estimating manifestation itself of side effect in patient during dialytic treatment - Google Patents

Abstract

PURPOSE: To enable to predict the onset of a side effect, by measuring at least patient's one hemodynamic value, calculating at least one rating corresponding to an average variation of parameter on a prescribed period, and discharge an alarm signal every time the parameter goes out of a prescribed range of safety value. CONSTITUTION: Signals proportional to the cardiac rate are detected by a sensor 5, processed at a low pass filter 11, and then stored in three groups of value in a calibrating memory 12 every time. A calculating device 17 performs linear regression according to designation by three cardiac rate groups stored in the memory 12, and, thereby determines coefficients 'ai' and 'bi' of corresponding line segments obtained by assigning f1, f2, and f3 in the calculation. When one of coefficients 'ai' is deviated from the established margin, comparators 24 and 25 send a '1' logic level signal to a corresponding input of OR gate 34 to make execute switching of each logic signal output from '0' to '1' and, following that, discharging of a control signal from an amplifier 35.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a prediction device that predicts the occurrence of side effects within a patient undergoing dialysis treatment. In particular, the invention makes it possible to monitor patients undergoing dialysis treatment and to detect symptoms such as nausea, vomiting, etc.
The present invention relates to a prediction device having the purpose of predicting the occurrence of undesirable side effects such as hypotension, headache, and in particular collapse.

[Prior art 1] Even in the current situation, the problem of avoiding the occurrence of side effects during dialysis has been addressed, but it has not yet been solved satisfactorily, and the following three basic interventions are needed: It depends on one of the steps.

According to the first step, the patient undergoes periodic (half-hourly or hourly) measurements of arterial blood pressure, heart rate, and possibly weight loss at the operator's, usually a nurse's, side. monitored by.

Needless to say, this cage vision is discontinuous and intermittent, and the responsibility for monitoring is left solely to the operator, who may intervene according to a visual assessment of the patient's condition or according to the patient's own complaints. They may even intervene. Obviously, this procedure does not allow corrective intervention at opportune times and therefore falls short of preventing all pathologies in a patient, which often appear very suddenly.

The second step is to use knowledge of the physiological dialysis process to adjust the structure of dialysis equipment so that it can perform the treatment with minimal risk of associated disturbances. The results are clearly superior to those obtained according to the first intervention procedure described above.

However, some instruments do not rely on any signals coming from the patient himself, but rather determine specific treatment parameters as close as possible to those considered (on a theoretical basis) to be optimal for the patient undergoing dialysis. It remains impossible to precisely prevent the development of collapse (certainly the most characteristic and most severe side effect) because the drug is programmed to obtain. Possible corrective or preventive interventions may in some cases even be left to the discretion of the operator.

The third step is to take into account the specific signals identified within the patient's body in preparation for performing the dialysis treatment. Such procedures are the subject of research in the field of dialysis, however, due to the difficulties that exist in identifying and measuring reliably basic physiological values as far as the patient's condition is concerned, statements such as has not yet been fully specified, either due to the difficulties that exist in defining effective strategies for processing and utilizing signals corresponding to .

SUMMARY OF THE INVENTION It is an object of the present invention to enable operators to intervene opportunistically and/or to automatically activate procedures that prevent Fa1 effects from occurring. An object of the present invention is to provide a device that can predict with high reliability the occurrence of side effects in a patient.

This object is achieved by the present invention, which relates to a device for predicting the occurrence of side effects within a patient's body during dialysis treatment. This device includes the following features:

A blood flow measuring device for measuring at least one hemodynamic value of a patient, said blood flow measuring device capable of providing at least one parameter corresponding to the variation of this hemodynamic value over time, with respect to a predetermined period of time. A signal processing device that calculates this parameter, i.e. at least one rating (ratino) corresponding to the average variation of the signal, and compares the value obtained for this rating with at least one reference value that defines a range of safe values. Comparison device, an alarm device which emits an alarm signal which can be used as a till @ signal whenever the value obtained for this rating deviates from the safe value range defined by the reference value.

BRIEF DESCRIPTION OF THE DRAWINGS In order to make the invention easier to understand, preferred embodiments are described below, purely by way of non-limiting example, with reference to the accompanying drawings.

Referring to FIG. 1, there is a possibility that side effects will occur in the body of a patient 2 during dialysis treatment performed using a dialysis machine 3 of a well-known type. Predict.

According to the invention, the prediction device 1 basically includes the following:

A sensor 5 capable of measuring the hemodynamic value of the patient and supplying a parameter corresponding to the variation of this hemodynamic value itself over time, processing the signal coming from the sensor 5 and a signal processing device 6 which calculates a rating corresponding to the variation of the above-mentioned parameter with respect to a period, and compares the value obtained for the above-mentioned rating with at least one reference value defining a predetermined range of safe values; a comparator 7, an alarm signal which can be used as an Ill III signal whenever the value obtained for the above-mentioned rating calculated by the signal processing device 6 exceeds the range of safe values defined by this reference value; The following detailed description assumes that the measured hemodynamic value is, for example, heart rate.

In view of this consideration, the sensor 5 includes, for example, a simple frequency meter, one of whose outputs is connected to a low-pass digital filter 11 forming part of the processing device 6 .

The basic function of this filter is to remove noise,
The purpose is to pass only the physiological signal emitted by the sensor 5 within the band of this signal itself.

This signal processing device 6 includes a storage device 12 that shifts from one storage element to another. In the case described, this storage device includes, for example, three equivalent storage elements 13, 14, 15, of which the first element 1
3 is connected to the output of filter 11.

The signal processing device 6 further includes a calculation device 17, the three signal inputs of the latter being connected in parallel to each other to the outputs of the storage elements 13, 14, 15 of the storage device 12,
and normalization device 118 has an input connected to the output of calculation device 17 and an output connected to the input of comparison device 7.

Calculator! t17 is, for example, the coefficient or slope of the line segment (see Fig. 3a), which in this case is obtained by considering the three values on the y-axis (values stored in storage elements 13, 14, 15). Provides the ability to perform least squares linear regression in terms of calculating “ai” and ah bHu.

Normalization device! The sole purpose of 18 is that for each line segment “al”, the equivalent value “a I i
The purpose is to calculate J+, for example, by applying the following equation.

The signaling device 6 is finally given a management modulo 20,
For example, it includes a microprocessor that controls the storage device 21 and all the components of the doffing device (the filter 11, the storage device 12 and the calculation device 17 and the normalization device [18]) from the point of view of regulating the signals between the components. connected to. The signal processing device 6 may conveniently be constituted by a microprocessor.

The comparator device 7 is of the conventional type and thus comprises a pair of threshold comparators 24, 25, each of which is connected to a processing device 6 (in this case a normalizer 18).
a first output connected to the output of and each sliding contact 26
．． 27 has a second human power connected to the potentiometer 28.29.

The potentiometers 28 and 29 are connected in series, and their respective opposite terminals are connected to terminals 31 and 32, to which the positive and negative poles of the DC power supply are respectively connected (in a manner not shown). .

The threshold comparators 24.25 are arranged as follows:
That is, the signals appearing at the respective outputs are at a "0" logic level until the signals appearing at these first inputs are within the reference voltage values picked up by the sliding contacts 26,27, while at the second output. Each time the appearing signal becomes higher or lower (respectively) than the above-mentioned reference signal value, it transitions to a "1" logic level.

The alarm device 9, which emits an alarm signal that can be used as a control signal, simply comprises an OR logic gate 34;
The two inlets are connected to the upstream comparators 24' and 25, respectively.
The downstream side is connected to the amplifier 35.

The output of the amplifier 35 is connected to a terminal 36 and an alarm 37, which typically includes an audible alarm 39 and an alarm lamp 39.

The output of low-pass filter 11 passes to terminal 118$1;
And the output of normalizer W118 is connected to terminal "b". Furthermore, the patient 2 is connected to an arterial blood pressure sensor 40, the output of the latter leading to terminal "C".

2a, 2b, and 2C, the motion of the electrical signals outputted from the terminals "a", "b", and "C" based on the time expressed in minutes is Va, Vb, respectively.
It is displayed as Vc.

In FIG. 2b, V26 and V27 represent two corresponding values of the respective threshold voltages taken up simultaneously by sliding contacts 26.27 of potentiometers 28.29.

Figure 3a shows the mathematical processing of the belief @Va<Figure 3a) to initially obtain a plurality of coefficients ai (Figure 3b) corresponding to the slope of the line segment obtained by linear regression according to the procedure described above. 3b and the successive normalization between -1 and +1 of the values obtained from these coefficients according to the representation in FIG. 3b. Finally, the method proposed by the invention prepares for the execution of the next sequential operation in this particular case. namely: measuring the heart rate of the patient 2; processing the measured heart rate signal so as to obtain at least one standard correlating to the variation of such heart rate over a predetermined period; Comparing the value of the octopus with at least one value defining a range of safe values, and checking whether this value obtained for the calculated standard moves outside the range of safe values defined by the reference values mentioned above. To emit an alarm signal that can be used as a control signal.

In general, a signal proportional to the heart rate is detected by the sensor 5 and processed in a low-pass filter 11, and then in each case the graduation is stored in groups of three values in the memory 12.

For example, the first three measured heart rate values f1. f2゜f3(
3a) is the memory element 13°14.15 of the memory device 12.
The subsequent value f4 occupies element 13 causing the values f3 and f2 to be shifted into elements 15 and 14, and pushes the value f1 out, and so on.

For each group of three heart rates stored in the storage device 12, the computing device 117 performs a linear regression according to the above specifications, thereby determining fl, f2 . Determine the coefficients "ai" and "b1" of the corresponding line segment obtained by taking f3 into the calculation, and then f2. The coefficients 11821% and "b2" of the corresponding line segment obtained by taking f3° f4 into the calculation are determined, and the same procedure is repeated.

In this way, the order of the coefficients “ai” is obtained (3rd b
(See figure) This is fed from the output of the computing device 17 and this sequence overall represents the slope of the heart rate signal detected by the sensor 5 and processed by the filter 11.

The next operation carried out within the normalizer 18 is to select the equivalent value "a' whose amplitude is between -1 and +1, as specified above.
The purpose is to adjust the above-mentioned coefficient ``ai'' so as to obtain ``i''. The next step that constitutes the test is the equivalent value “a′ i”
makes it possible to determine whether each of the values lies within a range of safe values bounded by two respective thresholds V27 and V28. This operation is performed using the comparator ff1
Comparator 24.25 and potentiometer 28 at 7
and 29.

In the event that one of the coefficients "a(") deviates from the established limits (see, for example, the value "al i4" in FIG. OR
to the corresponding inputs of the gates 34 to cause the switching of the respective logic signal output from "0" to "1" and the subsequent firing of the control signal from the amplifier device 35.

This emission of the control signal causes the audible alarm 38 and the alarm lamp 3
9 and the firing of an electrical signal to the terminal 36, which electrical signal is utilized for subsequent use, for example to automatically modulate certain parameters of the dialysis being carried out by the dialysis machine 3. be done.

Figure 2 depicts a clinical example in which "heart rate" hemodynamic values are measured every 10 beats, conventionally filtered by a digital bandpass filter, and "normalized gradient" It is obtained by circular regression over 15 samples (in this case, the digit-shifting memory F12 includes 15 memory elements).

If you look at this diagram in detail, you will find the following:
That is, an output signal vb falling above the lower threshold value V27 of the safe value range is generated at the lower start time t1 of the time limit (about 7 minutes or so), and coincident with the n-terminal time t2 of this time limit, the output signal vb is There is a sudden drop in arterial blood pressure, which causes the patient to have a cardiac-circulatory system deficiency.

It will be appreciated that an examination of clinical examples, such as those reported in FIG. 2, clearly demonstrates the importance of predictive behavior obtained using the predictive device provided by the present invention.

In fact, Tatsumi's communication was made at time t1, while the effective value of heart rate (approximately 61 beats/min) and mean arterial blood pressure (approximately 83 beats/min) are normal values for a patient undergoing dialysis. This means that the analysis of the instantaneous data provided by instruments capable of measuring these values is inappropriate for the purpose that the present invention seeks to achieve. shows the proof of.

An examination of the characteristics of the prediction device according to the invention reveals the following undeniable advantages.

Firstly, an effective and, above all, sufficiently early indication of the critical physiological situation is obtained. This allows early intervention and thus prevents the patient from suffering from cardio-circulatory system deception and all the sequelae associated with this situation (among others, heart disease from the patient).

By early use of the data provided by this predictive device, for example in a dialysis procedure operated using the dialysis machine 3, by simply signaling a possible emergency situation to the operator, the technician in charge can: Provisions can be made for automatic, timely and sufficient intervention.

Finally, it is clear that modifications and changes can be introduced to the prediction device 11 described above without departing from the scope of the invention.

Among other things, the analysis of the signal becomes much more complex if a set of standards is created, each of these standards having to be compared with at least one corresponding threshold.

Much more simply, the number of regression samples, ie the number of storage elements of the shift storage device, can also be varied dynamically by 4 degrees from one time period to another or according to the characteristics of the signal.

Furthermore, although heart rate was selected as the measured value,
It is also possible to measure other hemodynamic values that are temporally related to this hemodynamic value and consider selecting one or several operators of these (amplitude, heart rate, etc.). It will be done. By way of example, measurements and calculations for heartbeat amplitude signals and electrocardiogram signals can be performed by appropriate use of non-invasive heartbeat amplitude measurement devices and conventional electrocardiogram monitoring devices.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram of the in-vivo side effect prediction device for dialysis treatment patients according to the present invention, and FIG. Figure 2a is a waveform diagram of the three signals arranged in temporal correspondence. Figure 2a is a waveform diagram of the heart rate versus time after filtering in this specific clinical case. Figure 2a is a diagram showing the slope of the sequential line segment. A waveform diagram of the equivalent value obtained by calculating and normalizing “ai” using a normalization unit between −1 and +1 for the heart rate over time; FIG. 2C is a waveform diagram of the average blood pressure value over time; FIG. 3 is a graph diagram illustrating an example of signal processing performed by the prediction device shown in the block diagram of FIG. 1. [Explanation of symbols] 1: Device for predicting side effects in the patient's body during dialysis treatment 2: Patient 3: Dialysis machine 5: Sensor 6: Signal processing device 7: Comparison device 9: Alarm device 11: Filter 12: Digit storage Device 17: Calculation device 18: Normalization device 20: 21: 24°28°35: Management modulo storage device 25: Threshold comparator 29: Potentiometer amplifier device

Claims (1)

[Scope of Claims] (1) A blood flow measuring device that measures at least one hemodynamic value of a patient, the device for predicting side effects occurring in a patient's body during dialysis treatment, said blood flow measuring device capable of providing at least one parameter corresponding to a variation in a hydrodynamic value; a signal processing device capable of calculating at least one rating corresponding to an average variation of said parameter over a predetermined period of time; a comparison device for comparing the value obtained for said rating with at least one reference value defining a range of safe values; and the value obtained for said rating deviates from the range of safe values defined by said reference value. and an alarm device that emits an alarm signal that can be used as a control signal each time a prediction occurs. (2) The prediction device according to claim 1, wherein the blood flow measurement device includes at least one of a heart rate, an electrocardiograph signal, and/or a heartbeat amplitude measurement device. . (3) The prediction device according to claim 1 or 2, wherein the signal processing device includes a filter disposed downstream of the blood flow measuring device. (4) In the prediction device according to any one of claims 1 to 3, during operation, the signal processing device includes a storage device that stores the signal supplied by the blood flow measuring device; and a calculation device that calculates a rating. (5) The prediction device according to any one of claims 1 to 4, wherein the processing device includes a microprocessor. (6) The prediction device according to any one of claims 1 to 5, wherein the comparison device includes at least one threshold comparator. (7) The prediction device according to claim 6, wherein the comparison device includes at least one adjustment element that adjusts the threshold value of the threshold comparator. (8) The prediction device according to any one of claims 1 to 7, further comprising a signaling device that signals an abnormality that is driven by the warning device to issue the warning. The prediction device characterized by: (9) The prediction device according to claim 8, wherein the signal device is an acoustic type and/or an optical type. (10) The prediction device according to any one of claims 1 to 9, comprising a control device that can be operatively connected to the patient and is controlled by the alarm device. The prediction device characterized by: